Fix Smart Fortwo Gear Change Problems! Clutch Actuator Removal, Repair & Lubrication (451 Pure 2008)

Added: 2026-05-08

[00:00:00]In today's video, I'll be removing the clutch actuator from the Smart 451, dismantling it, and lubricating it.

[00:00:13]I'm Stephen from Auto Nights. Welcome to another video.

[00:00:16]Now, many people wrongly assume that the Smart 450 and 451 models have an automatic transmission. Well, they don't. They have an MTA, which is a manual transmission that is automated.

[00:00:30]Now, for reasons unknown, cars destined for the North American market actually had an automatic transmission style shifter.

[00:00:38]But, here in Europe, we have far less smoke and mirrors.

[00:00:41]And we've got a shifter that really tells it for what it is. So, despite there being a conventional clutch in this bell housing, there is no clutch pedal, no master cylinder, no clutch cable, no hydraulics. All of those components and all of those roles are taken up by this, the clutch actuator.

[00:01:00]And if you drive one of these cars, it really is only a matter of time before you will likely become acquainted with this component.

[00:01:14]It's worth stating that adjusting this clutch actuator is a bit of a dark art.

[00:01:18]It's adjusted mechanically. You can see these slots here allow it to be adjusted backwards and forwards in relation to the clutch internals. And it's also adjusted electronically via diagnostics.

[00:01:32]Of all the Smarts I've ever owned, this has one of the best gear changes I've ever known. So, I want that to remain the case. So, I'm going to be marking this so it goes back in exactly the same place.

[00:01:43]I'm not going to be covering adjustment in this video.

[00:01:47]Using a right-angle pick, I'm marking this to be sure it goes back in exactly the same place. With the ignition off, and it must stay off throughout.

[00:01:56]I'm disconnecting this plug.

[00:02:04]There are three torques bolts, one here, one here, and one up behind the back. And you need an E10 to take care of these. The rearmost one's a little difficult to see, but it's perfectly possible.

[00:02:19]Just a word of warning, these can seize.

[00:02:23]And if they do, well, I don't really have any suggestions. Maybe turn to God.

[00:02:28]I've been bitten before with these bolts, so I have replacements. And you can see the part number right here.

[00:02:35]You probably saw that spring back then.

[00:02:37]So, it is under a degree of tension.

[00:02:45]With all the fixings removed, we can lift it away from the car. And here it is, the clutch actuator.

[00:02:54]Now, when you think what this has to go through each day and the job that it performs, I mean, it springs into life for every gear change, every time you pull away, every time you stop. And this thing has a tough life.

[00:03:06]I mean, it takes the place of all the things I mentioned earlier, all the regular clutch components. So, I think these do well to last as long as they do.

[00:03:16]But, there's a bit of a flaw with these.

[00:03:18]And I'm going to take you inside to my kitchen where we can take this apart on the table and I can show you.

[00:03:24]Welcome to the Auto Nights kitchen table.

[00:03:27]Here we are dealing with an original Sachs actuator.

[00:03:31]Sachs, well, they're the gold standard for these.

[00:03:34]They're quite expensive if you need to replace this. I've paid as little as 300 before. You can pay up to five, depending on when companies have deals.

[00:03:44]AutoDoc had a great deal at one point, and I got one from there for a previous Smart.

[00:03:48]But, that's what you need. Now, there are some really awful cheap Chinese ones out there, way less money. Some people will swear by them, but some people are a bit cheap, aren't they? Uh they don't last the course. Some might say that they have in their case, but often they won't.

[00:04:05]So, what I'm going to do is get this cover off here.

[00:04:13]And to do that, I need to release a series of bolts. These little bolts are T20s.

[00:04:27]Awful lot of white powder coming out.

[00:04:30]No, it's not that. It's oxidized aluminum. There's one hidden in there as well.

[00:04:38]And then we can remove the cover.

[00:04:42]More oxidization in here.

[00:04:46]We can deal with that. But, with the cover removed, it's strikingly obvious to me that there's something kind of missing in here, and that's lubricant.

[00:04:55]You see, they're just a bit too stingy with it right from the start.

[00:05:00]I'm going to be cleaning this up, lubricating this, which will hopefully increase its lifespan.

[00:05:11]>> [music] [music] [music] [music] >> I think we can surmise that given that we've got a kind of silt in here, that this wasn't fully watertight.

[00:05:52]But, because this sits downwards, gravity will take care of most of it.

[00:05:56]Additionally, if you get a buildup of oxidization between the body of the actuator and this plastic, it will have the effect of separating this from the body, therefore reducing the effectiveness of this seal.

[00:06:14]I'll wash this properly in the sink.

[00:06:19]With everything beautifully clean, it's now time to turn my attention to lubricating the internals of this actuator.

[00:06:25]This is the grease I'm going to use, multi-purpose lithium-based with a high melting point. And hopefully, you can see in here the plastic gear there. I need to be applying it to that right the way around here.

[00:06:39]And there's also a worm drive there that comes out from the motor.

[00:06:48]I'm going to use a little brush to apply this.

[00:06:59]Now, if anyone's wondering why I'm not just moving this gear here to expose more of it to make it easier, there is a reason, and that's that when you get a new one of these, there are very clear instructions not to move it, not to disturb this. I want this going back exactly as it came off.

[00:07:18]It'll be hard to see, but there are a few further moving parts in here that I'm just going to grease.

[00:07:30]Little bit of grease on this cuz this spindle seats in the cover.

[00:07:35]And finally, I just put a bit around the perimeter to guard against any more of that oxidization.

[00:07:42]Okay, so it's really well lubricated in there.

[00:07:47]Time to put the cover back on.

[00:07:57]The cover is refitted.

[00:08:01]The shiny new bolts are refitted.

[00:08:03]The actuator is lined up with its old markings, and I retighten the bolts.

[00:08:09]They're tightened to 10 Newton meters.

[00:08:13]I then refit the electrical connector.

[00:08:15]Well, that's it for this one. Very pleased that's done. I just need to take the car out for a test drive to make sure everything's okay. There's no reason for anything to have changed because I refitted the actuator in exactly the same place as the previous one. And even while I was lubricating the internals, I didn't disturb anything or move any of the mechanism.

[00:08:35]As you could see, it was bone dry before, nicely lubricated now. And thinking about life in general, I can't think of any situation where anything is better without lubrication.

[00:08:46]I look forward to seeing you again in another one very soon. Don't forget to subscribe. Thank you, and goodbye.